This invention relates to a tool intended for chip removing or chip forming machining that comprises a base body and an insert seat for a replaceable cutting insert, which is adjustable by means of an adjusting mechanism located adjacent to the insert seat. The adjusting mechanism includes two jaws, a first one of which can press with a front surface against a rear surface on the cutting insert, and the second of which can press with a rearwardly directed pressure surface against at least one fixed support surface on the base body. Between the jaws a wedge member acts, that has the purpose of separating the jaws, if required, by being driven in between them so that the second jaw is pressed against the support surface at the same time as the first jaw presses out the cutting insert in the forward direction.
A cutting tool having an adjusting mechanism of the above generally mentioned kind is previously known from WO 98/43766. In said known tool, the adjusting mechanism includes an inside sleeve having a female thread for a set screw, as well as an outside sleeve, which is formed with two axial, diametrically opposed slots that separate two elastically deflectable segments in an upper part of the outside sleeve. In said segments, two jaws are formed, viz. a first essentially block-shaped jaw having the same width as the outer diameter of the outside sleeve and having a plane front surface that is pressed against a rear surface of the cutting insert, while a second jaw consists of a semi-circular, thickened wall portion, the width of which likewise corresponds to the outer diameter of the outside sleeve. The outside or the envelope surface of said thickened wall portion is pressed against a likewise semi-circular, fixed support surface recessed in the base body. A conical head on the set screw of the mechanism serves as a wedge member for separating the jaws in connection with fine-adjustment of the position of a cutting insert. Said conical screw head is in engagement with a similar conical space formed internally in the upper part of the outside sleeve, which space is delimited by two conical shaped partial surfaces on the inside of the segments. By screwing the set screw different distances into the female thread of the inside sleeve, the jaws are caused to separate by different distances from each other, whereby a cutting insert supporting against the block-shaped jaw of the adjusting mechanism is caused to assume different settings. By suitable choices of different parametersxe2x80x94primarily the conicity of the screw head and the pitch of the threadsxe2x80x94adjustment of the cutting insert may be effected with a fairly high dimensional accuracy, e.g. down to 1/100 mm.
However, a disadvantage of the adjusting mechanism included in the tool according to Publication WO 98/43766 is that the forces being applied to the cutting insert are transferred to the single support surface in a continuous train of forces through initially the block-shaped first jaw, and then the head of the set screw and finally the second jaw whose envelope surface abuts against the support surface in the base body. This means, among other things, that all said components are continuously exposed to varying stresses, which may impair the setting accuracy. Another detrimental consequence is that each cutting insert must be adjusted individually by manipulation of the set screw because the position of the cutting insert is always dependent on the state of the axial tightening of the set screw. In many practical applications for different tools, such as milling cutters, for attainment of a satisfactory machining result it is sufficient to set the different cutting inserts of the tool in a basic position, e.g., with the accuracy 1-2/100 mm, but then for other applications it is desirable to be able to set the cutting inserts with a closer accuracy, e.g. 1-2/1000 mm. It is an intricate and time-consuming task to then individually set all the cutting inserts on a milling cutter, by manipulation of the set screws, as is required in WO 98/43766.
The present invention aims at obviating the above-mentioned disadvantages of the previously known cutting tool and the adjusting mechanism thereof by providing a tool having an improved adjusting mechanism. Therefore, a primary object of the invention is to provide a tool having an adjusting mechanism which is normally exposed to only minimal stresses from the cutting insert, and which if required enables fine adjustment of the cutting insert to an extraordinarily good dimensional accuracy. It is also an aim to provide a tool having an adjusting mechanism built up of few components that are structurally uncomplicated as well as simple to manufacture.
According to the invention, at least the primary aim is attained by a tool for chip removing machining which comprises a base body and an insert-adjusting mechanism disposed on the base body. The base body presents an insert seat which is adapted to receive a cutting insert. The base body includes first and second fixed support surface structures disposed adjacent to the seat. The insert-adjusting mechanism is disposed adjacent to the seat and includes first and second jaws and a movable wedge member positioned between the jaws for spreading the jaws away from one another by a selected distance. The first jaw includes a front surface facing in a first direction toward the seat, and a first pressure surface structure facing in a second direction generally opposite the first direction. The front surface is adapted to engage a cutting insert and define a support position therefor. The second jaw includes a second pressure surface structure facing generally in the second direction. The jaws are positionable in a first position wherein the first pressure surface structure engages the first support surface structure, and the second pressure surface structure is spaced from the second support surface structure, wherein the front surface of the first jaw defines a basic support position adjacent to the seat. The jaws are positionable in a second position by being spread apart by the wedge member, wherein the second pressure surface structure engages the second fixed support surface structure and displaces the first jaw in the first direction, wherein the front surface of the first jaw defines an adjusted support position.
The invention also pertains to a method utilizing the tool.